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      <title>使用Reactive Streams与JUC提升应用性能 - 交互式测验</title>
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    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>使用Reactive Streams与JUC提升应用性能 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
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      <script>
        const quizData = [
  {
    "question": "根据文档，Reactive Streams 范式主要解决了传统同步阻塞模型在高并发场景下的什么核心问题？",
    "options": [
      "通过简化数据库连接池管理，提高数据访问效率。",
      "通过强制使用单线程模型，避免多线程带来的复杂性。",
      "通过异步非阻塞和背压控制，解决线程资源耗尽和系统性能下降的问题。",
      "通过内置的缓存机制，减少对外部服务的依赖。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档开篇就指出，传统同步模型在处理高并发请求时，会因I/O操作阻塞导致线程资源被大量占用和耗尽。Reactive Streams通过其核心的异步非阻塞范式和背压（Backpressure）机制，有效利用系统资源，防止消费者被过快的数据流压垮，从而根本上解决了这个问题，显著提升了系统的吞吐量和响应速度。",
    "source": "文档中「一、引言：为什么需要Reactive Streams？」和「二、Reactive Streams基础」部分",
    "hint": "想一想传统模型中，当一个线程等待I/O操作时会发生什么，以及这对系统整体资源的影响。"
  },
  {
    "question": "在Reactive Streams中，“背压（Backpressure）”机制的核心作用是什么？",
    "options": [
      "一种自动增加线程池大小以应对高负载的机制。",
      "允许数据发布者（Publisher）强制推送数据给订阅者（Subscriber）。",
      "一种错误处理机制，当发生错误时自动回退数据流。",
      "允许订阅者（Subscriber）根据自身处理能力，控制从发布者（Publisher）请求数据的速度。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "背压是Reactive Streams规范的灵魂。它是一种流量控制机制，允许消费者（Subscriber）向上游生产者（Publisher）传递其能够处理多少数据的信号（通过`Subscription.request(n)`），从而避免生产者发送数据的速度远超消费者的处理速度，防止“生产者压垮消费者”的情况发生。",
    "source": "文档中「2.2 核心概念」部分的“背压控制”",
    "hint": "这个机制是为了避免“生产者压垮消费者”。"
  },
  {
    "question": "Reactive Streams规范定义了四个核心接口。其中哪一个接口同时扮演数据发布者（Publisher）和数据订阅者（Subscriber）的角色？",
    "options": [
      "Subscription",
      "Processor",
      "Scheduler",
      "Executor"
    ],
    "correctAnswerIndex": 1,
    "explanation": "根据文档定义，Processor接口继承自Publisher和Subscriber，它既可以订阅上游的数据流（作为Subscriber），也可以在处理后将数据发布给下游（作为Publisher）。它在数据处理链中起到了承上启下的中间转换作用。",
    "source": "文档中「2.1 什么是Reactive Streams？」部分",
    "hint": "在数据处理流水线中，哪个角色既是消费者又是生产者？"
  },
  {
    "question": "文档中的代码示例展示了如何将Reactive Streams与JUC结合。`runOn(Schedulers.from(executor))` 这段代码的主要目的是什么？",
    "options": [
      "将后续操作的执行切换到指定的JUC线程池中进行，以实现异步任务调度。",
      "为数据流中的每个元素创建一个新线程。",
      "阻塞当前线程，直到数据流处理完成。",
      "限制数据流的最大并发数为线程池的大小。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "`runOn`操作符用于指定其下游操作链的执行线程上下文。通过`Schedulers.from(executor)`，可以将一个JUC的`ExecutorService`（线程池）包装成一个`Scheduler`，从而让数据处理任务（如`map`、`filter`等）在指定的线程池上异步执行，这是实现高性能并发处理的关键一环。",
    "source": "文档中「4.1 异步任务调度」部分",
    "hint": "这个操作符决定了数据处理任务在“哪个线程”或“哪个线程池”上运行。"
  },
  {
    "question": "根据文档「六、性能对比」表格，与传统同步模型相比，“Reactive Streams + JUC”模型在处理高并发任务时表现出什么显著优势？",
    "options": [
      "使用极少的线程就能达到更高的CPU利用率和QPS（每秒查询率）。",
      "内存占用更高，但平均响应时间更长。",
      "编程模型更简单，代码行数更少。",
      "对硬件的要求更低，可以在单核CPU上运行得更快。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "表格清晰地展示了，“Reactive Streams + JUC”模型可以用非常少的线程（例如16个）来处理大量并发请求，同时实现很高的CPU利用率（80%）和极高的QPS（9800）。而传统模型需要上千个线程，CPU利用率却很低，QPS也远不及前者，这体现了其卓越的资源利用效率。",
    "source": "文档中「六、性能对比：传统同步 vs Reactive Streams + JUC」部分",
    "hint": "请关注表格中“线程数”、“CPU利用率”和“最大QPS”这三列的巨大差异。"
  },
  {
    "question": "在“实战案例：高性能订单处理系统”中，`flatMap`操作符在处理订单流程中的核心作用是什么？",
    "options": [
      "将订单流中的每个订单异步地转换为一个新的流（例如 Mono），并将这些新流“扁平化”合并成一个单一的结果流。",
      "对订单流进行过滤，只保留有效的订单。",
      "将每个订单对象同步地转换为验证结果对象。",
      "为每个订单验证操作创建一个独立的线程并立即返回。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "`flatMap`是响应式编程中用于处理异步操作的核心操作符。它接收一个函数，该函数为流中的每个元素（如此处的订单）返回一个新的发布者（如`Mono`或`Flux`，代表一个异步操作）。`flatMap`会订阅这些内部发布者，并将它们发出的元素合并到最终的输出流中，从而实现异步操作链（如验证、计价、扣库存）的无缝衔接。",
    "source": "文档中「5.3 核心代码实现」部分",
    "hint": "`flatMap`通常用于将一个流中的元素，转换成另一个代表异步计算结果的流。"
  },
  {
    "question": "文档的“最佳实践与避坑指南”中提到了一个常见陷阱：“回调地狱（Callback Hell）”。这种情况通常是指什么？",
    "options": [
      "在回调函数中错误地使用了阻塞式API。",
      "由于异步操作的深度嵌套回调，导致代码难以阅读、理解和维护。",
      "由于过多的日志记录导致性能下降。",
      "服务器因无法处理大量回调请求而崩溃。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "“回调地狱”是异步编程中的一个经典问题。当一个异步操作依赖于另一个异步操作的结果时，就会形成层层嵌套的回调函数，代码结构呈金字塔状，可读性和可维护性极差。Reactive Streams通过链式调用的方式（如 a.then(b).then(c)），将复杂的异步流程扁平化，有效地避免了这个问题。",
    "source": "文档中「8.3 常见陷阱」部分",
    "hint": "这个问题会让你的代码缩进越来越深，形成一个难以维护的“金字塔”。"
  }
];
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                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
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                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  